# Insertion in binary search tree without recursion in scala

Scala program for Insertion in binary search tree without recursion. Here problem description and explanation.

```
// Scala program for
// iterative insert in binary search tree
class TreeNode(var data: Int,
var left: TreeNode,
var right: TreeNode)
{
def this(data: Int)
{
this(data, null, null)
}
}
class BinarySearchTree(var root: TreeNode)
{
def this()
{
this(null)
}
//insert a element
def addNode(data: Int): Unit = {
// Create a new node
var node: TreeNode = new TreeNode(data);
if (this.root == null)
{
// When adds a first node in bst
this.root = node;
}
else
{
var find: TreeNode = this.root;
// Add new node to proper position
while (find != null)
{
if (find.data >= data)
{
if (find.left == null)
{
// When left child empty
// So add new node here
find.left = node;
return;
}
else
{
// Otherwise
// Visit left sub-tree
find = find.left;
}
}
else
{
if (find.right == null)
{
// When right child empty
// So add new node here
find.right = node;
return;
}
else
{
// Visit right sub-tree
find = find.right;
}
}
}
}
}
// Display preorder
def preorder(node: TreeNode): Unit = {
if (node != null)
{
// Display node value
print(" " + node.data);
// Visit to left subtree
preorder(node.left);
// Visit to right subtree
preorder(node.right);
}
}
def inorder(node: TreeNode): Unit = {
if (node != null)
{
// Visit to left subtree
inorder(node.left);
// Display node value
print(" " + node.data);
// Visit to right subtree
inorder(node.right);
}
}
def postorder(node: TreeNode): Unit = {
if (node != null)
{
// Visit to left subtree
postorder(node.left);
// Visit to right subtree
postorder(node.right);
// Display node value
print(" " + node.data);
}
}
}
object Main
{
def main(args: Array[String]): Unit = {
var tree: BinarySearchTree = new BinarySearchTree();
/*
10
/ \
/ \
4 15
/ \ /
3 5 12
-------------
Build binary search tree
*/
tree.addNode(10);
tree.addNode(4);
tree.addNode(3);
tree.addNode(5);
tree.addNode(15);
tree.addNode(12);
// Display tree nodes
println("Preorder ");
tree.preorder(tree.root);
println("\nInorder ");
tree.inorder(tree.root);
println("\nPostorder ");
tree.postorder(tree.root);
}
}
```

**Output**

```
Preorder
10 4 3 5 15 12
Inorder
3 4 5 10 12 15
Postorder
3 5 4 12 15 10
```

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